Solar Terrestrial Activity Report [Image] Last update September 4, 2001 at 03:40 UTC. [Solar and geomagnetic data - last 4 weeks (updated daily)] [Solar wind and electron fluence charts (updated daily)] [Solar cycles 21-23 (last update September 1, 2001)] [Solar cycles 1-20] [Graphical comparison of cycles 21, 22 and 23 (last update September 1, 2001)] [Graphical comparison of cycles 10, 13, 17, 20 and 23 (last update September 1, 2001)] [Historical solar and geomagnetic data charts 1954-2001 (last update July 27, 2001)] Recent development The geomagnetic field was quiet to active on September 3. Solar wind speed ranged between 383 and 557 km/sec under the influence of a coronal stream. Solar flare activity was moderate. Solar flux was 198.7, the planetary A index was 17 (3-hour K indices: 3234 4434, Boulder K indices: 3233 5434). Region 9591 decayed slowly as it began to rotate over the southwest limb. Region 9596 was quiet and stable. Region 9599 decayed quietly. Region 9601 was mostly unchanged and has major flare potential. Region 9602 decayed slowly and was spotless by the end of the day. Region 9603 was quiet and stable. New region 9604 emerged very quickly near the southwest limb and has minor M class flare potential. New regions 9605 and 9606 emerged near the southeast limb. Region 9606 is developing at a moderate pace and could soon merge with region 9605. An interesting region is rotating into view at the southeast limb, this region is likely to produce at least minor M class flares. Flares and CMEs A total of 5 C and 2 M class events were observed on September 3. Region 9601 produced a C3.4 flare at 03:27, a C4.2 flare at 06:02, a C7.2 flare at 09:48, a C6.8 flare at 10:49 and an M1.1 flare at 17:16 UTC. A C9.0 flare with an associated moderate type II sweep was observed at the southeast limb at 01:58 UTC, probably with its source in the region now rotating into view. A long duration M2.5 event peaked at 18:41 UTC, this time a weak and fast type II radio sweep was observed. The source of this event is not certain but could be in the region at the southeast limb. The background x-ray flux is at the class C1 level. Coronal holes No obvious coronal holes are currently approaching geoeffective positions. Forecast The geomagnetic field is expected to be unsettled to active on September 4, possibly with one or two minor storm intervals. Quiet to unsettled is likely on September 5. Long distance medium wave (AM) band propagation along east-west paths over high and upper middle latitudes is poor to very poor. Coronal holes (1) Coronal mass M and X class flares (3) ejections (2) [Coronal hole indicator][CME indicator] [M and X class flare indicator] 1) Effects from a coronal hole could reach earth within the next 5 days. 2) Material from a CME is likely to impact earth within 96 hours. 3) There is a possibility of either M or X class flares within the next 48 hours. Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability. Active solar regions (Recent map) Solar Date Actual Location region numbered no. at Area Classification Comment sunspots midnight 9591 2001.08.21 6 S18W81 0260 FKO beta-gamma-delta 9596 2001.08.25 1 N22W38 0180 HSX 9597 2001.08.26 N19W54 plage 9599 2001.08.27 2 S18W31 0060 DSO 9601 2001.08.27 55 N14W06 0680 FKC beta-gamma 9602 2001.09.01 3 S07E02 0010 CSO 9603 2001.09.02 2 S09E49 0020 HSX 9604 2001.09.03 4 S21W61 0040 DSO beta-gamma 9605 2001.09.03 3 S20E53 0020 CSO 9606 2001.09.03 2 S17E57 0040 DSO Total number of sunspots: 78 Monthly solar data Month Average solar International sunspot Smoothed sunspot flux number number 2000.03 208.2 138.5 119.9 2000.04 184.2 125.5 120.8 cycle 23 sunspot max. 2000.07 202.3 170.1 119.7 2000.08 163.0 130.5 118.6 (-1.1) 2000.09 182.1 109.7 116.3 (-2.3) 2000.10 167.4 99.4 114.5 (-1.8) 2000.11 178.8 106.8 112.8 (-1.7) 2000.12 173.6 104.4 112.1 (-0.7) 2001.01 166.6 95.6 108.8 (-3.3) 2001.02 146.6 80.6 104.1 (-4.7) 2001.03 177.7 113.5 (102.8 predicted, -1.3) 2001.04 177.7 108.2 (102.0 predicted, -0.8) 2001.05 147.1 97.3 (100.5 predicted, -1.5) 2001.06 173.0 134.0 (97.7 predicted, -2.8) 2001.07 131.3 82.2 (95.9 predicted, -1.8) 2001.08 162.9 106.8 (96.4 predicted, +0.5) 2001.09 188.4 (1) 15.4 (2) (95.4 predicted, -1.0) 1) Running average based on the daily 20:00 UT solar flux value at 2800 MHz. 2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official international sunspot number is typically 25-40% less. This report has been prepared by Jan Alvestad. It is based partly on my own observations and interpretations, and partly on data from sources noted in solar links. Comments and suggestions are always welcome. ------------------------------------------------------------------------ [DX-Listeners' Club] [DX News] [StudyWeb]